The invention relates to an attachable/detachable process cartridge, an attachable/detachable drum cartridge, an attachable/detachable developer cartridge, and an image forming device capable of employing an attachable/detachable process cartridge, an attachable/detachable drum cartridge, and/or an attachable/detachable developer cartridge.
Electrostatographic image forming devices may include an optical system, a photosensitive device (e.g., a photosensitive drum), a charging device arranged in the vicinity of the photosensitive device, a developer device (e.g., developer roller), a transfer device (e.g., transfer roller), and a cleaning means. In general, electrostatographic image forming devices record images by forming an electrostatic latent image on a photosensitive device, forming a developer image by supplying developer to the formed electrostatic latent image on the photosensitive device, and transferring the developer image onto a recording medium. More particularly, for example, to form an image on a recording medium, the surface of the photosensitive drum is uniformly charged by the charging device before the surface is irradiated with a laser beam so as to form an electrostatic latent image corresponding to the image to be formed on the photosensitive drum. The latent image is then developed using a developer supplied by the developer roller such that a developer image is formed on the photosensitive drum. The developer image is then transferred to the recording medium by the transfer roller. After the visible image is transferred most, and preferably all, of any toner remaining on the photosensitive body is removed by the cleaning means.
In many of these image formation devices, many of the image forming components, such as, the photosensitive device, the charging device, the developer roller, the transfer roller and/or the cleaning means are provided, for example, in a process cartridge that is attachable to/detachable from the image forming device. Examples of such a process cartridge are disclosed in, for example, U.S. Pat. Nos. 6,041,203 and 6,546,217. Such process cartridges may be employed to facilitate, for example, replacement and/or maintenance operations of one or more of the components included in the process cartridge.
Process cartridges generally include a casing, in which the components of the process cartridge are housed, and on which a plurality of electrodes and driving gears are arranged. One of these electrodes may serve as a ground connection and another of these electrodes may feed electric power, from a power source arranged in the main body of the image forming device, to various components of the process cartridge. The driving gears interact with gears and/or members of the image forming device in order to drive various components of the process cartridge.
In order for the driving gears to properly engage with the corresponding gears/members of the image forming device, for example, components of the process cartridge must be properly positioned within the image forming device. In cases where the process cartridge includes a developer cartridge that detachably attaches to a drum cartridge, it is important, for example, to ensure that the arrangement of the developer cartridge with the drum cartridge is maintained during image forming processes. More particularly, in such a case, when an input driving force is applied to the developer cartridge, for example, a developer roller may rotate while in contact with the rotating photosensitive drum and such rotation may cause the developer cartridge to move relative to the drum cartridge. Such movement may hinder and/or delay the image forming process.
In particular, there is an increased demand for smaller and smaller image forming devices. To meet this increasing demand, smaller process cartridges must also be provided. At first glance, reducing the size of a process cartridge and/or image forming device may appear to be a straight forward task (e.g., reduce a size of all the components by X %). However, many factors and/or needs aggravate this deceivingly simple task and, those skilled in the art understand that, in fact, various design considerations and requirements make the process quite complex. Further, it is to be appreciated that, in recent years, the overall size of image forming devices and process cartridges has already been reduced substantially and for practicality purposes, there are some “minimum size” restraints on certain components of an image forming device and/or process cartridge. Thus, the playing field (i.e., amount of free/excess space available) has already been reduced substantially. Accordingly, those skilled in the art understand that the task of designing and implementing even smaller image forming devices and even smaller process cartridges while still providing practical devices and cartridges requires extensive experiment, thought and creativity.